I think they're doing that to know who's the genius that created Bitcoin when there was nothing like it before. At the same time they might want to get public attention because whoever searches for Satoshi gets attention of the public.

We all know that Satoshi used to be active part of this forum and he/she/they have totally left posting in 2010 and that's all we know. There's no need to know more about him/her/them because the product of Satoshi aka Bitcoin is still with us and has made many of us financially stable. Thanks to Satoshi for creating Bitcoin!